In the medical field, implantable leads are used with a wide variety of medical devices. For example, implantable leads are commonly used to form part of implantable cardiac pacemakers that provide therapeutic stimulation to the heart by delivering pacing, cardioversion or defibrillation pulses. The pulses can be delivered to the heart via electrodes disposed on the leads, e.g., typically near distal ends of the leads. In that case, the leads position the electrodes with respect to various cardiac locations so that the pacemaker can deliver pulses to the appropriate locations. Leads are also used for sensing purposes, or both sensing and stimulation purposes.
A number of challenges exist with respect to medical leads. In particular, new and improved lead designs are often needed to facilitate medical implantation to specific locations within a patient. For example, as more advanced and complex pacing techniques are developed, it becomes desirable to facilitate lead implantation at new cardiac locations. Some recent advancements in pacing have made use of non-conventional locations for delivery of pacing pulses, such as left ventricular locations, atrial roof locations and epicardium locations.
Cannulation, or lead placement, of the coronary sinus is a necessary part of the surgery that implements an IMD into the human body. A lead is placed in the great vein proximate the left ventricle to aid in the synchronous pumping of the ventricles. Placement of the lead in the great vein can be very difficult because of navigation issues resulting from undesirable angles and lack of lead maneuverability. Coronary sinus cannulation is a substantial barrier to predictably efficient implantation of coronary sinus lead.